Question

The hydrocarbon emissions at idling speed in parts per million (ppm) for automobiles of 1980 and 1990 model years are given for 20 randomly selected cars.

1980 models:

141	359	247	940	882	494	306	210	105	880
200	223	188	940	241	190	300	435	241	380

1990 models:

140	160	20	20	223	60	20	95	360	70
220	400	217	58	235	380	200	175	85	65

• (a) Compute the sample means for the two years and superimpose the two means on the plots. Compute sample standard deviation for the two years. Attach the screenshot of excel.

Answer 1

Answer:

a)